Hydraulic bumper jack



Aug. 2, 1960 Filed June 12, 1957 J. NOLDEN ETA!- HYDRAULIC BUMPER JACK 2 Sheets-Sheet 1 INVENTORS Jorm L. NOLDEN 2A J. SWARTZ.

BY W & PM

ATTORNEYS Aug. 2, 1960 J. L. NOLDEN 2,947,513

HYDRAULIC BUMPER JACK Filed June 12, 1957 2 sheetzsgsheet 2 FIG. 6.

IN V EN TORS HYDRAULIC BUMPER JACK John L. Nolden, 630 Resolano Drive, Pacific Palisades, Calif, and Ira Ii. Swartz, 11848W. Jefierson Bird, Culver City, Calif.; said Swartz assignor to said Nolden Filed June 12, 1957, Ser. No. 665,153

Claims. (Cl. 254-2) This invention relates generally to lifting apparatus and more particularly to a heavy duty air jack for lifting relatively bulky objects such as automobiles or trucks.

Many different types of jacks have been proposed heretofore. In any heavy duty jack such as employed in Warehouses or garages, it is important that safety means be incorporated in the jack to prevent inadvertent or accidental release of the jack in the event of a power failure. Further, it is desirable that the lifting portion of such jacks be capable of accommodating different sized loads and yet designed in such a manner that the jack may be readily moved about and easily stored when not in use.

With the above in mind, it is a primary object of the present invention to provide an improved heavy duty jack of extremely rugged construction incorporating positive safety features.

More particularly, it is an object to provide a jack of the above type which may be operated by conventional compressed air supplies generally available in garages, machine shops, and the like and which is provided with lifting means capable of extensional adjustment whereby different sized objects to be jacked up may be accommodated.

Another object is to provide a jack in which the lifting means may be compactly folded when not in use so that the jack may be conveniently moved about or stored.

These and many other objects and advantages of the present invention are attained briefly by providing a channel-iron base structure having two parallel upright members rigidly secured thereto. An air cylinder is positioned between these upright members and secured to the base structure. The movable portion of the jack comprises a carriage including a lifting portion adapted to receive cross beams pivotally mounted thereto for movement from a vertical folded position to a laterally ex tended position. These cross beams include feet members which may be adjustable both horizontally and vertically to accommodate any type of conventional load encountered. The carriage itself includes two upright racks spaced respectively adjacent the upright members of the base structure. A cross beam connects the upper portions of the racks and is centrally connected to a piston rod emerging from the upper end of the cylinder whereby extension of the piston rod will move both of the racks and the carriage upwardly. Each of the racks is provided with ratchet teeth and the upright base members include suitable ratchet dogs adjacent thereto and biased to seat in the teeth at any intermediate position of the carriage whereby should there be a failure in the cylinder, the carriage and lifting portion will be locked to the upright members against downward movement. Preferably, compressed air is employed to operate the jack although it will be evident that other hydraulic fluids may be used.

A better understanding of the invention will be had by referring to a preferred embodiment thereof as illustrated in the accompanying drawings, in which:

. ferent box opening.

Patented Aug. 2., 1960 ice Figure l is a perspective view of the jack of this invention in folded position;

Figure 2 is another perspective view of the lower portion of the jack illustrating parts of the lifting carriage in lateral extended position for placing under an object to be jacked up;

Figure 3 is a view of the upper portion of the jack looking in the direction of the arrow 3 of Figure 1;

Figure 4 is a view similar to Figure 3 showing the rack portions partially lifted;

Figure 5 is a rear perspective view of the jack carriage;

Figure 6 is a side elevational view of the jack in its uppermost position; and,

Figure 7 illustrates the jack of Figure 6 in its lowest position.

Referring to Figure l, the jack comprises a base structure 10 provided with a suitable roller 11 at its rear end and laterally forwardly projecting angle iron feet 12 and 13 at its front end to provide a relatively broad and stable base. Shown seated on the base of Figure 1 is a lifting carriage 14 having a cradle portion 15 within which is secured a cross plate 16. The cradle 15 and cross plate 16 are arranged to secure two lifting cross beams 17 and 18 pivoted at their inner ends as at 19 and 20 to the cross plate 16. Associated with the lifting beams 17 and 18 are suitable lifting feet 21 and 22.

The carriage 14 includes two parallel upwardly extending racks 23 and 24 provided with rack teeth on their forward edges as shown. The racks 23 and 24 are rigidly connected at their upper ends by a top plate member 25. The upper ends of the racks may also include laterally extending handles such as at 26 to facilitate movement of the jack about a garage floor on the rollers 11.

The base structure 10 itself includes two upwardly extending parallel support members 27 and 28 rigidly secured to the base structure at their lower ends and extending upwardly on either side of a stationary cylinder 29 also secured to the base structure 10. Thecylinder 29 is provided with a piston rod or plunger 30 which extends from its upper end and is secured to the underportion of the top plate member 25 as shown. The arrangement is such that fluid pressure introduced into the cylinder 29 will move the piston rod 30 upwardly to lift the top plate member 25 and racks 23 and 24 together with the carriage 14, all as a composite unit.

At the upper ends of the members 27 and 28 there is provided a dog support rod 31 secured at its ends to suitable dog levers adapted to engage the ratchet teeth in the racks 23 and 24 all as will become clearer as the description proceeds. The particular engagement or disengagement of these dogs is controlled by a handle 32 having its front end secured rigidly to the rod 3-1 and its other end extending rearwardly.

Referring now to Figure 2, the cross beams 17 and 13 are shown in their open, laterally extending position. It will be evident that the feet 21 and 22 may be moved horizontally back and forth as indicated by the double headed arrows such that the lifting portions of these feet may be spaced a desired distance. Further, because of the box channel construction of the feet members 21 and 22 they may be disposed at different distances above the cross beams by simply removing them and replacing them such that the cross beam passes through a dif- It will be noted in the enlarged view of Figure 2 that the carriage 14- includes at its upper ends adjacent the racks 23 and 24 inwardly directed stop projections 33 and 34. The stop projections 33 and 34 are arranged to co-operate with similar projections on the upper ends 3 of the support members 27 and 28 as will become clearer by referring to the enlarged view of Fig. 3.

In Figure 3, the upper co-operating stop members are indicated at 35 and 36 and as shown extend from and are rigidly secured to the support members 27 and 28. The stop members 35 and 36 also serve'to journal'thedog support rod 31. As shown, dogs 37 and 38 are respectiveiy secured to the extreme ends of rod 31. The handle 32 extends both downwardly and rearwardly and is rigidly secured to the rod 31 such that its weight will tend to rotate the rod in a direction to bias the dogs 37 and 38 against the front edges of the racks 23 and 24.

Referring now to Figure 4,. it will be noted that the dogs 37 and 38 are locked in two of the rack teeth in the racks 23 and 24. The rack teeth are designed such that upward movement of the racks 23 and 24 relative to the dogs 37 and 38 is notblocked whereas downward movement of the racks 23 and 24 relative to the dogs is not possible unless the dogs 37 and 38 are intentionally swung outwardly as by rotation of the rod 31 by lifting on the handle 32. Accordingly, in the event of pressure failure in the main cylinder, there is no possibility of the lifting portion of the jack descending. By the use of double racks as shown, very heavy loads may be supported notwithstanding the failure of hydraulic power.

It will be noted in both Figures 3 and 4 that the stop members 35 and 36 serving as the rotatable mounting means for the cross rod 31 are positioned such that they Willengage the inwardly directed stop projections 33 and 34 on the carriage shown in Figure 2 when the carriage portion is raised to a height corresponding approximately to the height of the support members 27 and 28. The length of the support members 27 and 28 and the positioning of the stops 35 and 36 thereon are designed such that engagement of the stops will take place prior to full extent of the piston rod from the cylinder. There is thus avoided the possibility of the cylinder head blowing Out.

In Figure 5, the rear portion of the carriage structure is shown as supporting two guide rollers 39 and 40 adapted to bear against the rear edges of the upright members 27 and 28. These rollers help to maintain the racks 23 and 24 in vertical alignment with the upright support members 27 and 28 as well as facilitate movement of the carriage.-

Figure 6 illustrates the carriage in its completely raised position with the stops 33 and 34 in engagement with the stops 35 and 36. Figure 7 illustrates the jack in its lowermost position.

The operation of the jack will be evident from the above description. In the event it is desired to jack up the end of a car, for example, the cross beams 17 and 18 are first swung downwardly from the position shown in Figure 1 to the position shown in Figure 2. The feet members 21 and 22 are then horizontally positioned on the beams at a proper separation distance to engage de sired structural members of the car frame. Compressed air may then be introduced into the main cylinder 29 to lift the piston rod 30 and associated racks and carriage structure.

As the carriage and racks rise, the dogs 37 and 38 will click into the successively passing rack teeth until a desired height is attained at which time the compressed air to the cylinder is cut off. While the compressed air already in the cylinder will sufiice to hold the carriage in its raised position, the dogs will nevertheless engage the particular rack teeth at the level at which the carriage is stopped to provide extra safety should the cylinder be defective.

To lower the jack, the dogs 37 and 38 are unlatched by the handle 32 and an outlet air valve in the cylinder opened to permit air to escape under the load on the piston. The carriage may be checked at any intermediate position if desired by simply releasing the handle 32.

It will be evident from the above description that the present invention provides a rugged lifting jack which is 4 extremely safe in the event of any power failure and which can be adjusted to accommodate different sized loads to be lifted. Further, the feature of the pivoted lifting beams 17 and 18 illustrated in Figures 1 and 2 enables the jack to be folded into a compact position and moved out of the way when not in use.

Modifications falling within the scope and spirit of the present invention will readily occur to those skilled in the art. The lifting jack is, therefore, not to be thought of as limited to the particular embodiment set forth for illus trative purposes.

What is claimed is:

l. A jack comprising, in combination: a base having two parallel supporting members rigidly secured thereto and extending upwardly; a vertical cylinder secured between said members and to said base, said cylinder having a piston rod extending from the upper end thereof; a carriage structure comprising a lifting portion adapted to seat on said base when said carriage is in a first position; said carriage including two parallel racks rigidly secured to either side thereof in horizontally spaced relationship and extending upwardly adjacent said supporting members on opposite sides of said cylinder, respectively, said racks having teeth in their front edges facing in the same direction; a plate member rigidly connecting the upper ends of said rack and rigidly connected at its central portion to the upper end of said piston rod whereby application of fluid pressure to said cylinder urges said piston rod upwardly to lift said carriage and racks relative to said base and supporting members from said first position to a second elevated position; stop members in the form of projections secured to the upper ends of said supporting members cooperating with said carriage to limit the upward movement of said carriage; a transverse rod extending at its opposite ends into said projections to be supported thereby; dogs secured to the opposite ends of said transverse rod outside said projections in horizontally spaced relationship to engage said racks simultaneously to block. the same from downward movement whereby loads horizontally off center are accommodated by said horizontally spaced relationship of said racks and dogs; and a handle rigidly secured to said transverse rod and extendingin a rearward direction to exert a rotational bias on said transverse rod, thereby urging said dogs against the teeth of said racks.

2. In a jack having a base with two parallel supporting members rigidly united therewith and extending upwardly therefrom, a vertical cylinder secured between said members and to said base, said cylinder having a piston rod extending upward therefrom, a carriage for lifting objects, said carriage being movable upward from a lower limit position at which the carriage is supported directly by said base, a cross member on said piston rod extending in both lateral directions therefrom, a pair of vertical members suspending said carriage from said cross member, said vertical members being adjacent said two parallel supporting members, respectively, the combination therewith of: teeth on the forward edges of said two vertical members, respectively, said teeth being directed downward and being exposed to view from the front of the carriage; a pair of pawls exposed to View from the front of the carriage and pivotally mounted on said two parallel supporting members, respectively, said pawls extending upwardly and rearwardly to engage said teeth simultaneously for stable support of the carriage at elevated positions from laterally spaced support points, said pawls being biased towards said teeth; and manually operable means to retract said pawls simultaneously out of engagement with said teeth.

3. In a jack having a base with two parallel supporting members rigidly united therewith and extending upwardly therefrom, a vertical cylinder secured between said mem bers and to said base, a piston in said cylinder hav-inga piston rod extending upwardly from the cylinder, a carriage for lifting objects, said carriage being movable upward from a lower limit position at which the carriage is supported directly by said base, a cross member on said piston rod extending in both lateral directions therefrom, a pair of vertical members suspending said carriage from said cross member, said vertical members being adjacent said two parallel supporting members, respectively, the combination therewith of: teeth on the forward edges of said two vertical members, respectively, said teeth being directed downward and being exposed to view from the front of the carriage; a pair of pawls exposed to view from the front of the carriage and pivotally mounted on said two parallel supporting members, respectively, said pawls extending upwardly and rearwardly to engage said teeth simultaneously for stable support of the carriage at elevated positions from laterally spaced support points, said pawls being biased towards said teeth; manually operable means to retract said pawls simultaneously out of engagement with said teeth; and stop means at elevated points on said two parallel supporting members cooperating with said carriage to limit the upward movement of the carriage to keep said piston from being thrust against the upper end of said cylinder.

4. A combination as set forth in claim 3 in which said pair of pawls are mounted on said stop means.

5. A jack according to claim 1, including inwardly directed projections secured to the upper portion of said carriage adapted to engage said stop members when said jack is fully extended whereby further extension of said piston from said cylinder is checked.

References Cited in the file of this patent UNITED STATES PATENTS 

